JPH01123258A - Method and device for feeding recording sheet of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To obviate generation of a deviation between a recording sheet and photosensitive body by a difference in the peripheral speed between a feed roller and the photosensitive body even if the long-sized recording sheet is fed by feeding the recording sheet between the photosensitive body and the feed roller while slackening the same downward. CONSTITUTION:A sheet length control means 13 is constituted of an original length detecting sensor disposed in the deep part of an original insertion base and reads the length of the original in the longitudinal direction thereof by detecting the front end and rear end of the original. The length of the recording sheet 7 is computed in a driving control means 40 by multiplying the read length by the copying magnification to be separately inputted by an operator, then a rotary cutter 14 is operated in compliance with the sheet length. Furthermore, an upper guide plate 23 is oscillated and rotated around a revolving fulcrum shaft 24 in an arrow E direction to slacken the recording sheet 7 uniformly in the transverse direction thereof. The wrinkling of the recording sheet in the transverse direction which is liable to arise with the broad recording sheet is thereby obviated.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention feeds recording paper for copying, copying film, etc. (hereinafter simply referred to as a recording sheet) of an electrophotographic copying machine in a loose manner before a transfer section. The present invention relates to a method for carrying out the method and an apparatus for carrying out the method.

(Prior Art) This type of recording sheet feeding device has conventionally been used, for example,
One disclosed in Japanese Unexamined Patent Publication No. 62-116950 is known.

There is a feeding roller that feeds the recording sheet toward a belt-shaped photoreceptor, and an alignment system that is interposed between the feeding roller and the photoreceptor and feeds the recording sheet while aligning it to the surface of the traveling photoreceptor. The recording sheet is configured to feed the recording sheet while loosening the recording sheet between the alignment roller and the feeding roller.

(Problems to be Solved by the Invention) In the above conventional example, the feeding speed of the alignment roller is configured to feed the recording sheet at a speed that is approximately the same as the moving speed of the traveling belt-shaped photoreceptor. However, no matter how precise the speed control is, there will always be a slight difference between the feeding speed of the alignment roller and the moving speed of the belt-shaped photoreceptor, and this will inevitably occur when recording a long recording sheet. There is a problem in that the minute differences are accumulated, leading to a decrease in the quality of the recorded image.

Moreover, the diameter of the alignment roller changes slightly depending on the environmental temperature, and the coefficient of friction also changes slightly depending on humidity and the material of the recording sheet, which has been an obstacle to improving the quality of recorded images.

The present invention has been made in view of these circumstances, and its main purpose is to improve the quality of recorded images.

(Means for Solving the Problems) The present invention achieves the above object, and the first invention is a recording sheet feeding method, which is configured as follows.

In other words, when the recording sheet is fed toward the photoconductor by the feeding roller, the recording sheet is initially fed at a feeding speed that is approximately equal to the moving speed of the photoconductor surface, so that the leading edge of the recording sheet is aligned with the surface of the photoconductor. This method is characterized by increasing the feeding speed of the feeding roller for a predetermined period of time after the recording sheet is in close contact with the photoreceptor, thereby loosening the recording sheet downward between the feeding roller and the photoreceptor.

Furthermore, the invention of tpJ2 is an apparatus for carrying out the above-mentioned feeding method, and is configured as follows.

That is, a sheet length defining means that defines the length of the recording sheet, a feeding roller that feeds the recording sheet toward the photoreceptor,
A recording sheet guiding means is interposed between the feeding roller and the photoreceptor and forms a guiding path for the recording sheet, and is connected to the feeding roller. and a drive control means for driving and controlling the feeding speed of the feeding roller and the raising and lowering of the lower guide plate, and the drive controlling means controls the feeding roller. Initially, the recording sheet is fed by driving at a feeding speed that is approximately equal to the moving speed of the photoreceptor surface, and based on counting the pulses from the pulse enhancer, it is determined that the leading edge of the recording sheet is in close contact with the photoreceptor surface. The system is characterized in that the lower guide plate of the photosensitive material guide means is driven downward based on the judgment, and the feeding roller is increased or decreased to thereby control the recording sheet to loosen it by a required amount.

(for production) Hereinafter, the operation will be explained based on the device invention.

When feeding the recording sheet towards the photoconductor with the feeding roller,
If the recording sheet is longer than a predetermined length, the drive control device
The feeding roller and the lower guide plate of the recording sheet guide means are driven and controlled as follows.

Initially, the feeding speed of the feeding roller is driven at approximately the same speed as the moving speed of the surface of the photoreceptor, and the recording sheet is fed along the guide path of the guide means.

Next, it is determined that the leading edge of the recording sheet has reached the surface of the photoreceptor and is in close contact, and the lower guide plate of the guide means is lowered, and the speed of the feeding roller is increased and decelerated as necessary. As a result, the recording sheet is fed downward between the feeding roller and the photoreceptor while being loosened by a certain amount. Therefore, even with a long recording sheet, unlike the conventional example, there is no risk of a speed difference between the feeding roller and the photoconductor resulting in relative displacement of the recording sheet with respect to the photoconductor, which would deteriorate the image quality. Since the length of the recording sheet is known by the sheet length determining means, the feeding roller is stopped when the trailing edge of the recording sheet passes through the guide path of the guide means, and the lower guide plate is raised to start recording. Ends the sheet feeding cycle.

(Example) Hereinafter, an example device according to the present invention will be described based on the drawings.

FIG. 1 is a schematic diagram of a recording sheet feeding device showing one embodiment. This feeding device is applied, for example, to an electrophotographic copying machine shown in FIG. 6 and fI%7. Note that FIG. 7 is a side view taken along the line ■-■ in FIG. 6.

This electrophotographic copying machine has a document scanning section 1 and an image recording section 2 arranged on the left and right, and a slit-shaped image of a document inserted into the document scanning section 1 is transferred to a U-shaped image recording section located below them. The image recording unit 2 is transmitted through a variable magnification projection optical system 3 having an optical axis of
The recording sheet 7 is projected onto the surface of the photosensitive drum 6 placed on the surface of the photosensitive drum 6, and the recording sheet 7 is fed to the photosensitive drum 6 by a recording sheet feeding device 12, which will be described later, so that the recording sheet 7 is brought into close contact with the photosensitive drum 6 electrostatically, and the recording sheet 7 is fed in a loose manner. While feeding, the toner image formed on the surface of the photosensitive drum 6 is transferred to a recording sheet 7, and the recording sheet is peeled off from the photosensitive drum 6 by a peeling and conveying drum 8 and sent to an open type fixing device 9, where it is fixed. The receiver is configured to discharge the recording sheets 7 onto a stand 10. Code 4 in Figure 6
5 is the document insertion table, 5 is the tray for receiving the ejected document, 1
1 is an operation panel.

The recording sheet feeding device 12, as shown in FIG.
6 and a pulse encoder 1 connected to the feed roller 16
8, a recording sheet guide means 20 interposed between the feeding roller 16 and the photosensitive drum 6, a sheet sensor 33 and a photoelectric type arranged above the guide means 20 in sequence in the traveling direction of the recording sheet 7. It comprises a slack amount detection sensor 34 constituted by a distance sensor and a drive control means 40 shown in FIG.

The sheet length regulating means 13 is comprised of a document length detection sensor disposed at the back of the document insertion table 4 shown in FIG. The length of the recording sheet 7 is calculated by the drive control means 40 by reading the length of the recording sheet 7 and multiplying the length by the copying magnification input separately by the operator, and the rotary cutter 14 is operated according to the sheet length. It has become. Code 15 in the figure
is a 7 cutter for driving the cutter. Note that in the case of a system in which the roll-shaped recording sheet 7 is not used, recording sheets of a plurality of sizes are stored in separate sheet cassettes, and the sheet cassette is selected, the sheet length regulating means 1 is
3 can also be replaced with a cassette selection key.

The feeding roller 16 includes a driving roller 16a and a driven roller 16b.
The drive roller 1 is configured as a nip roller consisting of
6a is rotatably driven by a variable speed drive motor 17. Further, a pulse encoder 18 is connected to the rotation shaft of the drive roller 16a, and the recording sheet 7
The feeding amount can be counted.

The recording sheet guide means 20 is interposed between the feeding roller 16 and the photosensitive drum 6, and the upper and lower guide plates 21 form a guide path 22 for the recording sheet 7, and the upper guide plate 23 of the guide path 22 The lower guide plate 27 of the guide path 22 is swingable.
is configured so that it can be lowered and raised.

That is, by swinging and rotating the upper guide plate 23 in the direction of the arrow E about the rotational support shaft 24, the recording sheet 7 is uniformly loosened downward across its width, and by doing so, in the case of a wide recording sheet. This eliminates the occurrence of wrinkles in the width direction. Note that the reference numeral 25 indicates the rotation support shaft 24.
2G is a stopper for the upper guide plate 23.

On the other hand, the lower guide plate 27 is rotated in the direction of arrow F about another rotational support shaft 28 to form a slack space for the recording sheet 7 below the guide path 22 . Note that the code 29 is the eccentric cam 3.
A transfer roller 31 rotates the eccentric cam 30 and rotates the lower guide plate 27.

The sheet sensor 33 is arranged at the start position A of the recording sheet 7, detects the leading edge and trailing edge of the recording sheet 7, and outputs a detection signal. That is, when the leading edge of the recording sheet 7 is detected, the feeding row 216 is stopped and the leading edge of the recording sheet 7 is kept waiting at the start position A, and when the trailing edge of the recording sheet 7 is detected, the feeding row 216 is stopped, and when the trailing edge of the recording sheet 7 is detected, the feeding row 216 is stopped and the leading edge of the recording sheet 7 is held at the start position A. After a predetermined period of time has elapsed, a signal is output to notify that the rear end has reached point B of the guide path 22, and to return the upper guide plate 23 and lower guide plate 27 to their original positions.

Note that 34 in FIG. 1 is a slack sensor composed of a photoelectric distance sensor, and this sensor adjusts the amount of slack of the recording sheet within a predetermined range.

As shown in FIG. 2, the drive control means 40 receives various control signals outputted from the microcomputer 41 and the microcomputer 41 via the output interface 43, and controls the various drive means 17, 25, 31, and 35. A feed roller drive circuit 44, an upper guide plate drive circuit 45, a lower guide plate drive circuit 46, and a cutter drive circuit 47 are provided for driving the rollers.

The microcomputer 41 is a central processing control unit (CPU)
41a, and a ROM4 that stores a predetermined control program.
1b and a RAM 41c that stores important data as appropriate, and receives signals inputted from various sensors 13, 33, 34, etc. via the human power interface 7/8 41, and performs various controls based on the operating procedure described later. Outputs signal H-K.

FIG. 3 is a 70-chart showing the operating procedure of the apparatus of the above embodiment. Hereinafter, the operation of the above device will be explained based on this flowchart.

First, in step S1, the document sensor serving as the sheet length determining means 13 detects the leading edge of the inserted document, and the feeding roller 16 is started at a standard speed approximately equal to the circumferential speed of the photosensitive drum 6.

At the same time, the pulses from the pulse encoder 18 are counted to measure the feeding amount of the recording sheet.

In step S2, the length of the recording sheet 7 to be fed is calculated by detecting the trailing edge of the document with the document sensor serving as the sheet length determining means 13, and the sheet quality is determined to be a predetermined length. (for example, the horizontal length of A). The recording sheet to be fed has a predetermined length. If it is longer, it is necessary to loosen the recording sheet 7, so the process proceeds to step S3; if it is shorter, there is no need to do so, and the process proceeds to step S812. That is, in the following cases when the recording sheet 7 has a certain length, the rear end of the recording sheet 7 is about to be released from the feeding roller 16 when the leading edge of the recording sheet 7 comes into close contact with the circumferential surface of the photosensitive V-ram 6. This is because the quality deterioration of the recorded image as described above will be to the extent that it will not cause any actual damage.

In step S, it is determined whether the leading edge of the recording sheet 7 has reached the zero point on the photosensitive drum 6 based on counting the pulse signals from the pulse encoder 18. This 0
The point is a position slightly forward of the position where the recording sheet 7 comes into close contact with the image forming surface of the photosensitive drum 6 by the transfer charger 36 and the toner image begins to be transferred onto the recording sheet 7.

In step S, the slack sensor 34 detects the recording sheet 7.
In order to detect the amount of slack, the slack sensor 34 starts operating, and the upper guide plate 23 and the lower guide plate 27 swing toward the lower side.

In step S, the slack sensor 33 detects the slack state of the recording sheet 7, and if it is on, that is, if the slack amount is less than or equal to a predetermined value of 1, the process advances to step S6 and the speed of the feeding roller 16a is increased. The recording sheet 7 is further loosened, and if it is in the OFF state, that is, the slack amount is greater than a predetermined amount, the process proceeds to step S, where the feeding roller 16a is decelerated to reduce the slack amount of the recording sheet 7. In other words, step S5・S
6.S7 automatically adjusts the slack amount of the recording sheet 7 within a certain range. Incidentally, the speed increase and deceleration are set to be about ±5% each of the standard feeding speed.

In step S8, based on counting the pulses from the pulse encoder 18, it is determined whether the recording sheet 7 has been fed by the required length, and when the required length has been reached, the rotary cutter 14 is activated to cut the recording sheet 7. At this time, since the recording sheet 7 is being fed in a slack state, no adverse effects such as vibrations occur due to cutting. Note that if a roll-shaped recording sheet is not used, steps S8 and S are unnecessary.

In step 1°, the sheet sensor 33 detects the trailing edge of the recording sheet 7 and then measures that a predetermined time has elapsed, thereby indicating that the trailing edge of the recording sheet 7 has reached point B on the guide path 22. In step S l l, the monitoring by the slack sensor is finished, and the upper and lower guide plates 23 and 27 are swung upward to return to their original positions.

In step S12, the leading edge of the subsequent cut recording sheet is placed at the starting position r! Have lA stand by. Note that step S12 is not necessary if a roll-shaped recording sheet is not used.

This completes the recording sheet feeding cycle of this copying machine, and the steps S, -S, and 2 are repeated in the same manner.

PIS 4 shows another embodiment in which the center part of the lower guide plate 27a of the guide means 20 is split to form a slack space, and FIG. 5 shows another embodiment in which the guide passage 22 is curved downward to form a slack space. Another embodiment in which the swing of 23 is omitted will be shown.

(Effects of the Invention) As is clear from the above description, according to the present invention, since the recording sheet is fed while being loosened downward between the photoreceptor and the feeding roller, a long recording sheet is fed. Even if you send
Unlike the conventional example, there is no relative misalignment between the recording sheet and the photoconductor due to the difference in peripheral speed between the feeding roller and the photoconductor, so the quality of the image transferred onto the recording sheet is improved. There is no risk of deterioration. This makes it possible to improve the quality of recorded images.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a recording sheet feeding device showing an embodiment of the present invention, FIG. 2 is a schematic diagram of the drive control means, and FIG. 3 is a flowchart showing the operation procedure by the drive control means.
4 and 5 are schematic diagrams showing other embodiments of the guide means, FIG. 6 is an external perspective view illustrating a copying machine to which the present invention is applied, and FIG. 7 is a diagram showing ■-■ in FIG. 6. It is a side view taken along the line. 6... Photosensitive member (photosensitive drum), 7... Recording sheet, 13... Sheet length determining means (original sensor), 1
6... Feeding roller, 18... Pulse encoder, 20... Guide means, 27... Lower guide plate, 3
4... Slack amount detection means (looseness sensor), 40... Drive control means. Figure 6 Figure 7

Claims (1)

[Claims] 1. Feeding a recording sheet to the surface of a moving photoreceptor and bringing it into close contact with the surface, and transferring the toner image formed on the surface of the photoreceptor to the recording sheet while feeding the recording sheet in a loose manner. In the recording sheet feeding method of an electrophotographic copying machine, when the recording sheet is fed toward the photoreceptor by the feeding roller, the recording sheet is initially fed at a feeding speed approximately equal to the moving speed of the photoreceptor surface. After the leading edge of the recording sheet comes into close contact with the surface of the photoreceptor, the speed of the feeding roller is increased for a predetermined period of time to loosen the recording sheet downward between the feeding roller and the photoreceptor. A recording sheet feeding method 2 for an electrophotographic copying machine characterized by: an electrophotographic copying machine 3 according to claim 1 in which the recording sheet is loosened when the recording sheet is longer than a predetermined length; A recording sheet feeding device for an electrophotographic copying machine that feeds a recording sheet to the body surface and brings it into close contact with the body surface, and transfers a toner image formed on the surface of a photoreceptor onto the recording sheet while feeding the recording sheet in a loose manner. a sheet length regulating means for regulating the length of the recording sheet; a feeding roller for feeding the recording sheet toward the photoreceptor; and a recording sheet guide path interposed between the feeding roller and the photoreceptor. a recording sheet guide means configured to be able to lower and raise the lower guide plate of the guide path; a pulse encoder connected to the feeding roller to count the feeding amount of the recording sheet; and drive control means for driving and controlling the feeding speed and the raising and lowering of the lower guide plate, and the drive controlling means drives the feeding roller at a feeding speed that is substantially equal to the moving speed of the surface of the photoreceptor at the beginning. Feeding the recording sheet, and determining that the leading edge of the recording sheet has come into close contact with the surface of the photoreceptor based on counting pulses from the pulse encoder, and driving the lower guide plate of the photosensitive material guide means downward. , a recording sheet feeding device for an electrophotographic copying machine, characterized in that drive control is performed so that the recording sheet is loosened by a required amount by increasing and decelerating a feeding roller.